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< td align = "right" valign = "center" > < img src = "logo32.png" align = "right" width = "64" height = "32" border = "0" > < / td > < / tr > < / table > < h1 align = center > TQEventLoop Class Reference< / h1 >
< p > The TQEventLoop class manages the event queue.
< a href = "#details" > More...< / a >
< p > < tt > #include < < a href = "tqeventloop-h.html" > tqeventloop.h< / a > > < / tt >
< p > Inherits < a href = "tqobject.html" > TQObject< / a > .
< p > < a href = "tqeventloop-members.html" > List of all member functions.< / a >
< h2 > Public Members< / h2 >
< ul >
< li class = fn > < a href = "#TQEventLoop" > < b > TQEventLoop< / b > < / a > ( TQObject * parent = 0, const char * name = 0 )< / li >
< li class = fn > < a href = "#~TQEventLoop" > < b > ~TQEventLoop< / b > < / a > ()< / li >
< li class = fn > enum < a href = "#ProcessEvents-enum" > < b > ProcessEvents< / b > < / a > { AllEvents = 0x00, ExcludeUserInput = 0x01, ExcludeSocketNotifiers = 0x02, WaitForMore = 0x04 }< / li >
< li class = fn > typedef uint < a href = "#ProcessEventsFlags" > < b > ProcessEventsFlags< / b > < / a > < / li >
< li class = fn > void < a href = "#processEvents" > < b > processEvents< / b > < / a > ( ProcessEventsFlags flags, int maxTime )< / li >
< li class = fn > virtual bool < a href = "#processEvents-2" > < b > processEvents< / b > < / a > ( ProcessEventsFlags flags )< / li >
< li class = fn > virtual bool < a href = "#hasPendingEvents" > < b > hasPendingEvents< / b > < / a > () const< / li >
< li class = fn > virtual void < a href = "#registerSocketNotifier" > < b > registerSocketNotifier< / b > < / a > ( TQSocketNotifier * notifier )< / li >
< li class = fn > virtual void < a href = "#unregisterSocketNotifier" > < b > unregisterSocketNotifier< / b > < / a > ( TQSocketNotifier * notifier )< / li >
< li class = fn > void < a href = "#setSocketNotifierPending" > < b > setSocketNotifierPending< / b > < / a > ( TQSocketNotifier * notifier )< / li >
< li class = fn > int < a href = "#activateSocketNotifiers" > < b > activateSocketNotifiers< / b > < / a > ()< / li >
< li class = fn > int < a href = "#activateTimers" > < b > activateTimers< / b > < / a > ()< / li >
< li class = fn > int < a href = "#timeToWait" > < b > timeToWait< / b > < / a > () const< / li >
< li class = fn > virtual int < a href = "#exec" > < b > exec< / b > < / a > ()< / li >
< li class = fn > virtual void < a href = "#exit" > < b > exit< / b > < / a > ( int retcode = 0 )< / li >
< li class = fn > virtual int < a href = "#enterLoop" > < b > enterLoop< / b > < / a > ()< / li >
< li class = fn > virtual void < a href = "#exitLoop" > < b > exitLoop< / b > < / a > ()< / li >
< li class = fn > virtual int < a href = "#loopLevel" > < b > loopLevel< / b > < / a > () const< / li >
< li class = fn > virtual void < a href = "#wakeUp" > < b > wakeUp< / b > < / a > ()< / li >
< / ul >
< h2 > Signals< / h2 >
< ul >
< li class = fn > void < a href = "#awake" > < b > awake< / b > < / a > ()< / li >
< li class = fn > void < a href = "#aboutToBlock" > < b > aboutToBlock< / b > < / a > ()< / li >
< / ul >
< hr > < a name = "details" > < / a > < h2 > Detailed Description< / h2 >
The TQEventLoop class manages the event queue.
< p >
< p > It receives events from the window system and other sources. It
then sends them to < a href = "tqapplication.html" > TQApplication< / a > for processing and delivery.
< p > TQEventLoop allows the application programmer to have more control
over event delivery. Programs that perform long operations can
call either processOneEvent() or < a href = "#processEvents" > processEvents< / a > () with various
ProcessEvent values OR'ed together to control which events should
be delivered.
< p > TQEventLoop also allows the integration of an external event loop
with the TQt event loop.
< p > To use your own instance of TQEventLoop or TQEventLoop subclass create
it before you create the TQApplication object.
< p > See also < a href = "application.html" > Main Window and Related Classes< / a > and < a href = "events.html" > Event Classes< / a > .
< hr > < h2 > Member Type Documentation< / h2 >
< h3 class = fn > < a name = "ProcessEvents-enum" > < / a > TQEventLoop::ProcessEvents< / h3 >
< p > This enum controls the types of events processed by the
< a href = "#processEvents" > processEvents< / a > () functions.
< ul >
< li > < tt > TQEventLoop::AllEvents< / tt > - All events are processed
< li > < tt > TQEventLoop::ExcludeUserInput< / tt > - Do not process user input events.
( ButtonPress, KeyPress, etc. )
< li > < tt > TQEventLoop::ExcludeSocketNotifiers< / tt > - Do not process socket notifier
events.
< li > < tt > TQEventLoop::WaitForMore< / tt > - Wait for events if no pending events
are available.
< / ul > < p > < p > See also < a href = "#processEvents" > processEvents< / a > ().
< h3 class = fn > < a name = "ProcessEventsFlags" > < / a > TQEventLoop::ProcessEventsFlags< / h3 >
A < tt > typedef< / tt > to allow various ProcessEvents values to be OR'ed together.
< p > < p > See also < a href = "#ProcessEvents-enum" > ProcessEvents< / a > .
< hr > < h2 > Member Function Documentation< / h2 >
< h3 class = fn > < a name = "TQEventLoop" > < / a > TQEventLoop::TQEventLoop ( < a href = "tqobject.html" > TQObject< / a > * parent = 0, const char * name = 0 )
< / h3 >
Creates a TQEventLoop object, this object becomes the global event loop object.
There can only be one event loop object. The TQEventLoop is usually constructed
by calling < a href = "tqapplication.html#eventLoop" > TQApplication::eventLoop< / a > (). To create your own event loop object create
it before you instantiate the < a href = "tqapplication.html" > TQApplication< / a > object.
< p > The < em > parent< / em > and < em > name< / em > arguments are passed on to the < a href = "tqobject.html" > TQObject< / a > constructor.
< h3 class = fn > < a name = "~TQEventLoop" > < / a > TQEventLoop::~TQEventLoop ()
< / h3 >
Destructs the TQEventLoop object.
< h3 class = fn > void < a name = "aboutToBlock" > < / a > TQEventLoop::aboutToBlock ()< tt > [signal]< / tt >
< / h3 >
< p > This signal is emitted before the event loop calls a function that
could block.
< p > < p > See also < a href = "#awake" > awake< / a > ().
< h3 class = fn > int < a name = "activateSocketNotifiers" > < / a > TQEventLoop::activateSocketNotifiers ()
< / h3 >
< p > Activates all pending socket notifiers and returns the number of
socket notifiers that were activated.
< h3 class = fn > int < a name = "activateTimers" > < / a > TQEventLoop::activateTimers ()
< / h3 >
< p > Activates all TQt timers and returns the number of timers that were
activated.
< p > TQEventLoop subclasses that do their own timer handling need to
call this after the time returned by < a href = "#timeToWait" > timeToWait< / a > () has elapsed.
< p > Note: This function is only useful on systems where < tt > select()< / tt > is
used to block the eventloop. On Windows, this function always
returns 0. On MacOS X, this function always returns 0 when the
GUI is enabled. On MacOS X, this function returns the documented
value when the GUI is disabled.
< h3 class = fn > void < a name = "awake" > < / a > TQEventLoop::awake ()< tt > [signal]< / tt >
< / h3 >
< p > This signal is emitted after the event loop returns from a
function that could block.
< p > < p > See also < a href = "#wakeUp" > wakeUp< / a > () and < a href = "#aboutToBlock" > aboutToBlock< / a > ().
< h3 class = fn > int < a name = "enterLoop" > < / a > TQEventLoop::enterLoop ()< tt > [virtual]< / tt >
< / h3 >
< p > This function enters the main event loop (recursively). Do not call
it unless you really know what you are doing.
< h3 class = fn > int < a name = "exec" > < / a > TQEventLoop::exec ()< tt > [virtual]< / tt >
< / h3 >
Enters the main event loop and waits until < a href = "#exit" > exit< / a > () is called, and
returns the value that was set to exit().
< p > It is necessary to call this function to start event handling. The
main event loop receives events from the window system and
dispatches these to the application widgets.
< p > Generally speaking, no user interaction can take place before
calling < a href = "#exec" > exec< / a > (). As a special case, modal widgets like < a href = "tqmessagebox.html" > TQMessageBox< / a >
can be used before calling exec(), because modal widgets call
exec() to start a local event loop.
< p > To make your application perform idle processing, i.e. executing a
special function whenever there are no pending events, use a
< a href = "tqtimer.html" > TQTimer< / a > with 0 timeout. More advanced idle processing schemes can
be achieved using < a href = "#processEvents" > processEvents< / a > ().
< p > < p > See also < a href = "tqapplication.html#quit" > TQApplication::quit< / a > (), < a href = "#exit" > exit< / a > (), and < a href = "#processEvents" > processEvents< / a > ().
< h3 class = fn > void < a name = "exit" > < / a > TQEventLoop::exit ( int retcode = 0 )< tt > [virtual]< / tt >
< / h3 >
< p > Tells the event loop to exit with a return code.
< p > After this function has been called, the event loop returns from
the call to < a href = "#exec" > exec< / a > (). The exec() function returns < em > retcode< / em > .
< p > By convention, a < em > retcode< / em > of 0 means success, and any non-zero
value indicates an error.
< p > Note that unlike the C library function of the same name, this
function < em > does< / em > return to the caller -- it is event processing that
stops.
< p > < p > See also < a href = "tqapplication.html#quit" > TQApplication::quit< / a > () and < a href = "#exec" > exec< / a > ().
< h3 class = fn > void < a name = "exitLoop" > < / a > TQEventLoop::exitLoop ()< tt > [virtual]< / tt >
< / h3 >
< p > This function exits from a recursive call to the main event loop.
Do not call it unless you really know what you are doing.
< h3 class = fn > bool < a name = "hasPendingEvents" > < / a > TQEventLoop::hasPendingEvents () const< tt > [virtual]< / tt >
< / h3 >
< p > Returns TRUE if there is an event waiting, otherwise it returns FALSE.
< h3 class = fn > int < a name = "loopLevel" > < / a > TQEventLoop::loopLevel () const< tt > [virtual]< / tt >
< / h3 >
< p > Returns the current loop level.
< h3 class = fn > void < a name = "processEvents" > < / a > TQEventLoop::processEvents ( < a href = "tqeventloop.html#ProcessEventsFlags" > ProcessEventsFlags< / a > flags, int maxTime )
< / h3 >
Process pending events that match < em > flags< / em > for a maximum of < em > maxTime< / em > milliseconds, or until there are no more events to
process, which ever is shorter.
< p > This function is especially useful if you have a long running
operation and want to show its progress without allowing user
input, i.e. by using the < a href = "#ProcessEvents-enum" > ExcludeUserInput< / a > flag.
< p > NOTE: This function will not process events continuously; it
returns after all available events are processed.
< p > NOTE: Specifying the < a href = "#ProcessEvents-enum" > WaitForMore< / a > flag makes no sense and will
be ignored.
< h3 class = fn > bool < a name = "processEvents-2" > < / a > TQEventLoop::processEvents ( < a href = "tqeventloop.html#ProcessEventsFlags" > ProcessEventsFlags< / a > flags )< tt > [virtual]< / tt >
< / h3 >
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
< p > Processes pending events that match < em > flags< / em > until there are no
more events to process.
< p > This function is especially useful if you have a long running
operation and want to show its progress without allowing user
input, i.e. by using the < a href = "#ProcessEvents-enum" > ExcludeUserInput< / a > flag.
< p > If the < a href = "#ProcessEvents-enum" > WaitForMore< / a > flag is set in < em > flags< / em > , the behavior of
this function is as follows:
< p > < ul >
< p > < li > If events are available, this function returns after processing
them.
< p > < li > If no events are available, this function will wait until more
are available and return after processing newly available events.
< p > < / ul >
< p > If the < a href = "#ProcessEvents-enum" > WaitForMore< / a > flag is < em > not< / em > set in < em > flags< / em > , and no
events are available, this function will return immediately.
< p > NOTE: This function will not process events continuously; it
returns after all available events are processed.
< p > This function returns TRUE if an event was processed; otherwise it
returns FALSE.
< p > < p > See also < a href = "#ProcessEvents-enum" > ProcessEvents< / a > and < a href = "#hasPendingEvents" > hasPendingEvents< / a > ().
< h3 class = fn > void < a name = "registerSocketNotifier" > < / a > TQEventLoop::registerSocketNotifier ( < a href = "tqsocketnotifier.html" > TQSocketNotifier< / a > * notifier )< tt > [virtual]< / tt >
< / h3 >
< p > Registers < em > notifier< / em > with the event loop. Subclasses need to
reimplement this method to tie a socket notifier into another
event loop. Reimplementations < em > MUST< / em > call the base
implementation.
< h3 class = fn > void < a name = "setSocketNotifierPending" > < / a > TQEventLoop::setSocketNotifierPending ( < a href = "tqsocketnotifier.html" > TQSocketNotifier< / a > * notifier )
< / h3 >
< p > Marks < em > notifier< / em > as pending. The socket notifier will be
activated the next time < a href = "#activateSocketNotifiers" > activateSocketNotifiers< / a > () is called.
< h3 class = fn > int < a name = "timeToWait" > < / a > TQEventLoop::timeToWait () const
< / h3 >
< p > Returns the number of milliseconds that TQt needs to handle its
timers or -1 if there are no timers running.
< p > TQEventLoop subclasses that do their own timer handling need to use
this to make sure that TQt's timers continue to work.
< p > Note: This function is only useful on systems where < tt > select()< / tt > is
used to block the eventloop. On Windows, this function always
returns -1. On MacOS X, this function always returns -1 when the
GUI is enabled. On MacOS X, this function returns the documented
value when the GUI is disabled.
< h3 class = fn > void < a name = "unregisterSocketNotifier" > < / a > TQEventLoop::unregisterSocketNotifier ( < a href = "tqsocketnotifier.html" > TQSocketNotifier< / a > * notifier )< tt > [virtual]< / tt >
< / h3 >
< p > Unregisters < em > notifier< / em > from the event loop. Subclasses need to
reimplement this method to tie a socket notifier into another
event loop. Reimplementations < em > MUST< / em > call the base
implementation.
< h3 class = fn > void < a name = "wakeUp" > < / a > TQEventLoop::wakeUp ()< tt > [virtual]< / tt >
< / h3 > < p > < b > Note:< / b > This function is < a href = "threads.html#threadsafe" > thread-safe< / a > when TQt is built withthread support.< / p >
< p > Wakes up the event loop.
< p > < p > See also < a href = "#awake" > awake< / a > ().
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